Can I take pictures without buying a memory card when I buy a SLR camera?

When a SLR camera doesn't have a memory card, it can only take a few pictures by the built-in cache. This is for trial operation (if you want to transfer the pictures cached in the machine to the computer, use the data cable to upload them, and don't put the memory card in the card slot). Veterans of photography have the habit of checking the spare flash memory card and battery before going out to shoot, and also put a spare card in the camera bag, which will not cause embarrassment because they forget to bring the card or the battery is dead. Flash cards are expensive at present, so why not buy some spare ones?